Regarding sterilization monitoring, the CDC Guidelines for Infection Control in Dental Health-Care Settings --- 2003 states:
Monitoring of sterilization procedures should include a combination of process parameters, including mechanical, chemical, and biological. These parameters evaluate both the sterilizing conditions and the procedure's effectiveness.
Mechanical techniques for monitoring sterilization include assessing cycle time, temperature, and pressure by observing the gauges or displays on the sterilizer and noting these parameters for each load. Some tabletop sterilizers have recording devices that print out these parameters. Correct readings do not ensure sterilization, but incorrect readings can be the first indication of a problem with the sterilization cycle.
Chemical indicators, internal and external, use sensitive chemicals to assess physical conditions (e.g., time and temperature) during the sterilization process. Although chemical indicators do not prove sterilization has been achieved, they allow detection of certain equipment malfunctions, and they can help identify procedural errors. External indicators applied to the outside of a package (e.g., chemical indicator tape or special markings) change color rapidly when a specific parameter is reached, and they verify that the package has been exposed to the sterilization process. Internal chemical indicators should be used inside each package to ensure the sterilizing agent has penetrated the packaging material and actually reached the instruments inside. A single-parameter internal chemical indicator provides information regarding only one sterilization parameter (e.g., time or temperature). Multiparameter internal chemical indicators are designed to react to >2 parameters (e.g., time and temperature; or time, temperature, and the presence of steam) and can provide a more reliable indication that sterilization conditions have been met (254). Multiparameter internal indicators are available only for steam sterilizers (i.e., autoclaves).
Because chemical indicator test results are received when the sterilization cycle is complete, they can provide an early indication of a problem and where in the process the problem might exist. If either mechanical indicators or internal or external chemical indicators indicate inadequate processing, items in the load should not be used until reprocessed.
Biological indicators (BIs) (i.e., spore tests) are the most accepted method for monitoring the sterilization process because they assess it directly by killing known highly resistant microorganisms (e.g., Geobacillus or Bacillus species), rather than merely testing the physical and chemical conditions necessary for sterilization. Because spores used in BIs are more resistant and present in greater numbers than the common microbial contaminants found on patient-care equipment, an inactivated BI indicates other potential pathogens in the load have been killed.
Correct functioning of sterilization cycles should be verified for each sterilizer by the periodic use (at least weekly) of BIs. Every load containing implantable devices should be monitored with such indicators, and the items quarantined until BI results are known. However, in an emergency, placing implantable items in quarantine until spore tests are known to be negative might be impossible.
Manufacturer's directions should determine the placement and location of BI in the sterilizer. A control BI, from he same lot as the test indicator and not processed through the sterilizer, should be incubated with the test BI; the control BI should yield positive results for bacterial growth.
Dual Indicator Sterilization Pouches/Bags
Some of the new dual indicators state that they conform with the CDC's recommendations and there is no need for a monitoring strip anymore. One asks is this accurate?
Built-in indicators do serve the same purpose as placing the strip inside the cassette. Utilizing sterilization pouches/bags with built-in internal and external indicators does eliminate the need to insert another indicator strip into the cassette. However, dental infection control experts do recommend that the sterilization pouches contain built-in internal/external indicators that are multi-parameter steam indicators verses those that only measure one parameter.
Many pouches on the market today now feature built-in internal and external indicators, which Dr. Chris Miller says is an advancement that saves clinicians time and money previously spent purchasing and inserting indicator strips into the pouches.*
But again, it is our understanding that not all built-in indicators may be multi-parameter.
(Cheryl Wolf CDA BS)
*Infection Control and Management of Hazardous Materials for the Dental Team, 5th. Edition. By Miller C. .Pages 135-143.